The present invention pertains to a dock leveler and cross traffic leg mechanisms for supporting a dock leveler, in particular.
In the art of dock levelers and related devices a conventional configuration includes a ramp which is mounted in a pit at the edge of a freight dock for pivotal movement to provide a support surface between the dock and the loadbed of a vehicle to facilitate loading and unloading of the vehicle. Because of the various heights of vehicle loadbeds which may be parked at a loading dock, dock levelers should be adapted to move between a position wherein the dock leveler ramp extends above the surface of the dock and also to a position where the ramp may extend below the generally horizontal dock surface to provide a support for vehicle loadbeds which are, in themselves, at an elevation above or below the dock surface. Dock levelers should also be capable of being supported in a position wherein the ramp is substantially coplanar with the dock surface to permit traffic across the ramp when the dock leveler is inactive, for example.
In order to provide support for the dock leveler ramp in the so-called cross traffic or stored position of dock leveler, so-called cross traffic legs have been developed which are intended to support the ramp, generally at the end of the ramp opposite the end which is connected for pivotal movement with respect to the dock. Examples of prior art cross traffic leg arrangements are disclosed in U.S. Pat. No. 3,902,213 and 4,279,050.
However, there has been a continuing need to provide improved cross traffic legs for dock levelers which provide support for the dock leveler ramp to be substantially coplanar with the dock surface in the stored position of the ramp to permit so called cross traffic and also to allow for movement of the ramp to working positions inclined above the dock surface and declined below the dock surface. These desiderata have been sought with prior art cross traffic leg mechanisms which are either somewhat complicated, unreliable or difficult to manufacture. It is to overcome the deficiencies of prior art dock leveler cross traffic leg configurations and to provide improvements in such mechanisms that the present invention has been developed.
The present invention provides an improved cross traffic leg mechanism for a dock leveler.
In accordance with one aspect of the present invention, a dock leveler is provided with cross traffic legs which include telescoping leg members which are mounted for pivotal movement on the distal end of a dock leveler ramp to accommodate various inclined and declined positions of the ramp with respect to the dock surface, for supporting the ramp in the cross traffic position and for supporting the ramp if the ramp suddenly declines from an elevated position or selected below dock level positions
In accordance with another aspect of the present invention, cross traffic legs for a dock leveler are provided which include moveable lock members, respectively, which move in conjunction with movement of a pivotable ramp extension lip member. The leg lock members move between (1) a working position to lock the cross traffic legs in a predetermined position when the lip is in a pendant position and (2) a retracted position to unlock the cross traffic legs for floating or telescoping movement when the lip is in a working or extended position with respect to the leveler ramp. Moreover, when the ramp is being moved between a generally horizontal stored position and a declined or below dock position the cross traffic legs are operable to accommodate such movement.
In accordance with another aspect of the present invention, a cross traffic leg arrangement for a dock leveler is provided wherein, in the stored position of the dock leveler ramp, the cross traffic legs are locked so that the ramp extension lip and the ramp cannot be raised from the exterior of the loading dock to gain access to the interior of a building at which the dock leveler is disposed.
In accordance with still another aspect of the invention, a dock leveler ramp is provided with two spaced apart cross traffic support legs which are characterized by somewhat tubular leg members mounted for limited pivotal movement on the underside of the ramp, include telescoping leg members mounted thereon for limited movement and further include leg lock members which may be moved from a position to lock the telescoping leg members in extended positions to support the ramp in the ramp cross traffic position and positions of the lock members which permit telescoping movement of the leg members to allow the dock leveler ramp to move to selected below dock working positions.